Some of the in-game achievements are not described very well, so here is some clarification/help.
"Get 200 people without using them" -- Translation - Kill 200 enemies without using the Rage mode or the wizard's power
"Submit your score" -- Translation - fully complete out the main game, and after stage 20, click to submit your score. You actually can't submit score in any other circumstance, counter-intuitively.
"Complete a level with 100%" -- Translation - Have 100% accuracy of your clicks in a stage, as well as no missed coins, and no damage to your castle, purchase at least one upgrade, and start the next stage. Careful as enemies killed near the edge of the screen might spill their coins off-screen, and be sure to collect all coins before they vanish.
"Play the game twice" -- Translation - Play the main game, lose the game and choose to continue. Merely playing the game however many times you like will never award this as it should be labeled more like continue after a game over rather than play the game twice.
I believe those are the really unfair ones due to very bad labeling. There's of course "Find the hidden screen" but I believe that's correctly-labeled and intended to be secret and those good at finding those sorts of things shouldn't have any trouble with it. It's no different from finding similar secret screens or options in other games.